The main components of a drive train in a motor vehicle are a drive unit and a transmission. A transmission converts torque and rotation speed, and hereby converts the available traction force of the drive unit. This present invention relates to the operating of a drive train which has at least one transmission and one hybrid drive as drive unit.
A method for operating an automatic transmission and a hybrid drive of a motor vehicle is known by US 2005/0221947 A1 whereby, on one hand, a clutch is positioned between a combustion engine of the hybrid drive and an electric motor of the hybrid drive and, on the other hand, an additional clutch is positioned between the electric motor and the automatic transmission. At the time, when the drive train is driven exclusively by the electric motor of the hybrid drive, the combustion engine of the hybrid drive, in accordance with the state of the art, can be started in a way that, during the execution of an upshift by the automatic transmission of the drive train, the clutch, positioned between the combustion engine of the hybrid drive and the electric motor, is engaged. In accordance with US 2005/0221947 A1, the electric motor of the hybrid drive hereby serves to start the combustion engine of the hybrid drive, whereby the start of the combustion engine takes place during the execution of an art shift, thus at interrupting the traction force. The start of the combustion engine, during the execution of an upshift, can lead to a reduction of the driving comfort.